Detergent compositions normally contain surfactants which tend to produce suds (foam) when agitated in aqueous solution. For many applications, especially in automatic laundry and dishwashing machines, excess suds production is a serious problem with detergent compositions and with many detergent surfactants it is necessary to add suds inhibiting compounds, hereinafter referred to as antifoaming agents, in order to achieve acceptable sudsing characteristics.
Silicone-based materials, for example polydimethylsiloxane, are commonly used in detergent compositions as antifoaming agents. These silicone-based antifoaming agents, referred to generically hereinafter as silicone antifoaming agents, are known to be very useful at low levels in various detergent compositions. These silicone antifoaming agents have been incorporated singly or in combination with various solid materials such as silica aerogels and xerogels and hydrophobic silicas of various types, into solid and liquid detergent formulations.
There are, however, limitations to incorporating silicone antifoaming agents into certain detergent compositions. Silicone antifoaming agents are not as effective when used with suds boosting (high-sudsing) surfactants like fatty acid amides and alkanolamides, betaines, sulfobetaines and amine oxides, all of which tend to produce stable foams. Higher levels of silicone antifoaming agents are typically needed when used with such high-sudsing surfactants which can add substantially to formulation costs and with liquid formulations, in particular, can cause aesthetic problems. Silicone antifoaming agents by design are insoluble in water and are suspended as an emulsion with nonionic surfactants. At high levels, the silicone emulsion can be visible thus leading to a clouding or hazy appearance.
The foregoing considerations involving antifoaming agents for use in detergent compositions, especially high-sudsing detergent compositions, indicates that there is a continuing need to provide such compositions with improved antifoaming agents therein. Accordingly, it is an object of the present invention to provide a low-sudsing detergent composition with a highly effective antifoaming agent therein, and further to provide such a low-sudsing composition which also contains a high-sudsing surfactant. It is yet a further object of the present invention to provide such a composition wherein the high-sudsing surfactant is an amine oxide surfactant.